The ultra-hot, ultra-pressurized steam is used to drive some of the most advanced power plant turbines in the world, which crank out electricity. Generators at these power plants typically run on fossil fuels such as coal or natural gas. That’s because until now, solar power could only achieve the subcritical heat level. Subcritical power plants operate at lower pressures, which allows bubbles to form that introduce inefficiencies in power generation.

But not here. At the solar thermal test plant at CSIRO in Newcastle, Australia, researchers used more than 600 directional mirrors pointed at two towers housing solar receivers and turbines. In the test, the researchers generated steam at a pressure of 3,400 psi and 1,058 degrees Fahrenheit. At that temperature, liquid water is converted directly to steam. No bubbles. Zero inefficiency.

And if you haven’t gotten the point yet. Here it is: A solar power plant that generates supercritical steam lowers the cost of generating electricity and negates the need to ever use fossil fuels to achieve the same result.

“It’s like breaking the sound barrier; this step change proves solar has the potential to compete with the peak performance capabilities of fossil fuel sources,” said Alex Wonhas, CSIRO’s Energy Director.